While in high school, Varitek was involved in many school activities and a model student. In addition to outstanding academic performance, Jason was Lake Brantley High School's third baseman and relief catcher. Brantley's first line catcher was Jerry Thurston, himself a pro prospect. In 1990, the Patriots won the state championship.[9] He was also a member of the 1992 U.S. Olympic team and won the Dick Howser Trophy for National Collegiate Player of the Year.

Varitek was drafted in the 23rd round of the 1990 amateur draft by the Houston Astros, but opted to attend college instead of pursuing professional baseball at that time.[10]

Varitek played five summers in the Cape Cod Baseball League with the Hyannis Mets. In 1993, he hit .371 while winning both the league batting championship and MVP. He was drafted 21st overall in the first round by the Minnesota Twins in 1993,[11] but opted to return for his senior year of college. Following graduation, Varitek signed with agent Scott Boras and was drafted by the Seattle Mariners in the first round of the 1994 amateur draft, with the 14th pick overall.[12] A pioneer of the loopholes in the draft process, Varitek signed with the St. Paul Saints in the independent Northern League[13] before agreeing to terms with the Mariners, and consequently did not enter the Mariners' minor league system until 1995. When he finally did join the franchise, Varitek was sent to the AA affiliate Port City Roosters where he first met pitcher and longtime teammate Derek Lowe. He was traded with Lowe to the Red Sox during the 1997 season in return for relieverHeathcliff Slocumb, often cited as one of the best trades in the Red Sox's favor in recent history.[14]

Varitek was called up for a single game on September 24, 1997, collecting a single in his only at bat. During the 1998 season, Varitek split time with incumbent catcher Scott Hatteberg playing in 86 games.[3] Varitek showed signs of things to come in the season, and with a strong spring training following the season, Varitek earned the starting catcher position.

Looking forward on building more success from the year before, the 2000 season was a disappointment offensively, producing a .248 average with only 10 home runs and 65 RBI, as the Red Sox failed to qualify for post-season play.[3] Prior to the 2001 season, Varitek signed a 3-year, $14.9 million contract with Boston. Varitek went on a hitting hot streak, having a .310 average at one point and on May 20, 2001, he homered three times in a single game before a broken left elbow injury sidelined the catcher for nearly the rest of the season, as Varitek dove to catch a foul ball on June 7. The play went on to be a top Web Gem for the month of July in 2001. Varitek finished the season with a .293 average, 7 home runs, and 25 RBI in 51 games played.[3]

Varitek returned to the Red Sox lineup full-time in the 2002 season. The return did not go smoothly, however, as Varitek struggled to find himself at the plate. Despite not reaching his full offensive potential,[3] pitchers and coaches alike began to notice how much Varitek's preparation and knowledge of the game was helping the pitchers. His study habits and extra hours of work with pitchers would soon become his defining attribute. Varitek and the Red Sox entered the 2003 season with a renewed fire to reach the playoffs after missing in the previous three years. Varitek instantly became a leader in the clubhouse which management tried to portray as working class, featuring new faces such as Kevin Millar, David Ortiz, Bill Mueller, and Todd Walker along with original players Trot Nixon and Lou Merloni. 2003 was Varitek's best year to date and earned his first All-Star selection after the fans voted him on with the All-Star Final Vote. He was hitting .296 with 15 HRs and 51 RBIs[16] going into the all-star break and finished the season off with a solid .273 average, 25 HRs and 85 RBIs,[3] all career highs. The Red Sox earned a Wild Card berth and their first playoff appearance since 1999, before losing the 2003 ALCS to the New York Yankees.

In 2004, Varitek compiled a career-high .296 batting average with 18 home runs and 73 RBI. During a nationally televised game on July 24, 2004, Varitek shoved his glove into the face of the Yankees' Alex Rodriguez after Rodriguez was hit by a pitch and gestured towards pitcher Bronson Arroyo, causing a bench-clearing brawl. Though he was ejected (along with Rodriguez) from the game following the incident, the Red Sox, spurred on by the fight, came from behind to win 11–10. It is also sometimes regarded as the turning point in the Red Sox season, as they posted MLB's best record after the melee. Boston culminated the season with its first World Series championship in 86 years, after being the first team to overcome a three games to none deficit in the ALCS vs. the New York Yankees.

At the end of the year, Varitek became a free agent and signed a 4-year, $40-million contract with the Red Sox.[17] Because of his performance both on and off the field, the franchise awarded Varitek with the captaincy.

After Varitek's re-signing, the Red Sox appointed him to be the third team captain in franchise history, following hall of famers Carl Yastrzemski (1969–1983) and Jim Rice (1986–1989).[17] He became one of the three captains in Major League Baseball. Derek Jeter of the NY Yankees, and Paul Konerko of the Chicago White Sox were the others. He maintained his captaincy until his retirement before the 2012 season.

In 2006, Varitek represented the United States in the World Baseball Classic, playing in three games. He made the most of his playing time, hitting a grand slam against Team Canada allowing Team USA to narrow an 8–2 lead down to 8–6. Team Canada, however, kept the lead in the upset victory.

On July 18, 2006, Varitek played his 991st game at catcher for the Boston Red Sox, breaking Carlton Fisk's club record. That game was a home game vs. Kansas City, during which Varitek's achievement was recognized before the bottom of the 5th inning (after the game was official and couldn't be cancelled due to weather). Varitek received a standing ovation from the sellout crowd at Fenway Park for a few moments before play resumed. On July 31, 2006, Varitek was injured rounding the bases in a 9–8 victory over the Cleveland Indians (his 1000th career game as catcher), but said he believed the initial injury to the knee occurred while he was blocking home plate to make the tag against the Angels Mike Napoli on July 29, 2006. He had surgery on August 3, 2006, to repair torn cartilage in his left knee. Varitek returned to the Red Sox lineup on September 4, following a short rehabilitation assignment in Pawtucket.

On September 19, 2006, Varitek was honored during a pre-game ceremony as the first Red Sox catcher to catch 1,000 games. He was presented with a special award by Hall of Famer Carlton Fisk, who held the Boston club record with 990 career games caught before Varitek surpassed it. Varitek caught his 1000th game on July 31 and by the evening of the ceremony had appeared in 1,009 games behind the plate. That same night, Varitek also received the 2006 Red Sox Heart and Hustle Award from the local chapter of the Major League Baseball Players Alumni Association, which is presented to a player exemplifying the values, tradition, and spirit of the game of baseball.

Varitek at bat in 2008

In 2007, Varitek and the Red Sox returned to the World Series, winning for the second time in four years. During the season, Varitek recorded his 1000th career hit. On May 19, 2008, he caught Jon Lester's no-hitter, giving him a Major League record of having caught four separate no-hitters in his career.

In honor of being captain, Varitek released Captain Cabernet, a charity wine with proceeds benefiting Pitching In For Kids and Children's Hospital Boston.[18][19]

At the end of the 2008 season, Varitek opted for free agency, rejecting arbitration that would give him a salary close to the $10 million he made in 2008.[20] Reports in the Boston Globe suggested that his agent, Scott Boras, was using New York Yankee catcher Jorge Posada's four-year, $52.4 million deal as a benchmark for negotiations.[21] On February 6, 2009, Varitek signed a new one-year deal with the Red Sox worth $5 million with a $5 million club option, or a $3 million player option, for 2010.[14][22] During the 2009 season, Varitek's numbers were similar to his dismal 2008 season, with slightly more home runs (14), doubles (24) and runs batted in (51), and a higher slugging percentage (.390) despite a lower batting average (.209) and fewer at bats (425). He eventually became the backup catcher when the Red Sox acquired All-Star Victor Martinez on the July 31 trade deadline.

On December 2, 2010, Sports Illustrated, on its website SI.com, reported that Jason Varitek signed a one-year, two-million dollar deal to stay with the Boston Red Sox for the 2011 season.[23] The deal was finalized on December 10.[24] With the addition of Jarrod Saltalamacchia, Varitek usually came off the bench during the 2011 season, playing in 68 games, hitting .221 with 11 home runs, 36 RBI, with a .300 on-base percentage

After the 2011 season, Varitek became a free agent once again, and was offered a minor league contract, with an invitation to spring training, by the Red Sox. On March 1, 2012, at Jet Blue Park in Fort Myers, Florida, Varitek officially announced his retirement.

On September 27, 2012, Red Sox General Manager Ben Cherington announced that Varitek had been named special assistant to the general manager.[1][25] In that role, Cherington said Varitek would be involved in areas such as "major league personnel decisions, evaluations, and mentorship and instruction of young players."[25]

Varitek has three daughters from his first marriage, Kendall, Alexandra and Caroline. He and his first wife, the former Karen Mullinax, divorced in 2008. Varitek married Catherine Panagiotopoulos on November 26, 2011 and their first child, Liv Jordan Varitek, was born on May 27, 2012.[32] Varitek's brother Justin Varitek is a member of the Rollins College baseball team coaching staff.[33] Varitek is a Christian.[34]